ABSTRACT:In this study, we present the experimental results for the crosslinking process of a commercial polyester resin based on measurements of the spin lattice relaxation time T 1 of protons, as function of the crosslinking time evolution. Multiexponential decomposition of the evolution of magnetization measured in inversion-recovery experiments is performed. The population of ''rigid'' and ''mobile'' nuclear spin sites was estimated as function of time evolution. In analogy to the usual monomer conversion u, site conversion from ''mobile'' to ''rigid'' sites u M were also estimated as a function of time evolution and initial concentrations of the reagents. The multiexponential decomposition approach of T 1 relaxation data allows one to follow crosslinking processes.

Este trabalho apresenta um modelo teórico e um estudo experimental sobre oscilações amortecidas realizado através de um sistema oscilador não convencional, com a utilização de materiais de baixo custo e de fácil aquisição contendo uma de uma esfera metálica maciça oscilando em um tubo transparente, aberto nas extremidades e levemente curvado, contendo três fluidos diferentes: ar, água e óleo de motor automotivo. O processo de obtenção dos dados foi realizado através vídeo-análise valendo-se do software Tracker. Os resultados obtidos possibilitaram constatar sua semelhança com o modelo teórico com a correção de Ladenburg para oscilações amortecidas em regime supercrítico(esfera em óleo) e em regime subcrítico (esfera no ar e na água).

OCT evaluated the biofilm adhesion over dental enamel and bulk fill composite resins. Samples were exposed to Staphylococcus aureus and Candida albicans and scanned by OCT. Resins showed higher Candida colonization, compared to enamel group.

The laser ablation in liquid environment (LALE) technique is a straightforward experimental technique with few controllable parameters, capable to provide extreme pressure and temperature conditions during target ablation without the need for dedicated systems to provide those variables. Additionally, we can state that LALE can be considered a low-cost experimental technique, with few steps and a clean synthesis method, by which a wide variety of materials can be synthesized with high yield. The majority of studies published in the literature using this technique seem to be limited only to the synthesis of metal nanoparticles, metal oxides, nitrates and semiconducting. However, in order to extend the synthesis potential of this technique, in this chapter we are going to demonstrate that with the appropriate choice of reactants, solvent, target materials and the solid-liquid interface interactions we will be able to prepare more complex molecules such as carbonate compound Pb 3 (CO 3) 2 (OH) 2 , metal-organic frameworks (MOFs), luminescent metal-organic frameworks (LMOFs), highly dispersed CdS quantum dots and magnetic materials. Also for each material synthesized, we are going to propose a mechanism to explain its preparation using the LALE technique.